ML20154Q719
| ML20154Q719 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 10/21/1998 |
| From: | Katz P BALTIMORE GAS & ELECTRIC CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9810260056 | |
| Download: ML20154Q719 (2) | |
Text
a PETER E. KATZ Baltimore Gas and Electric Company Plant General Manager Calvert Cliffs Nuclear Power Plant Calvert Cliffs Nuclear Power Plant 1650 Calvert Cliffs Parkway Lusby, Maryland 20657 410 495-4101 1
I October 21,1998 U. S. Nuclear Regulatory Commission Washington, DC 20555 ATTENTION:
Document Control Desk
SUBJECT:
Calvert Cliffs Nuclear Power Plant Unit No.1; Docket No. 50-317 Soecial Renort - Wide Range Noble Gas Monitor i
The attached special report is submitted in accordance with Calvert Cliffs Updated Final Safety Analysis Report Section 15.3.1, Contingency Measure B.2.2. The report is required due to the Unit 1 Wide Range Noble Gas Monitor having less than the required minimum number of operable channels.
Should you have questions regarding this matter, we will be pleased to discuss them with you.
Very truly yours, for Peter E. Katz Plant General Manager PEK/KRE/ dim Attachment I
cc:
R. S. Fleishman, Esquire H. J. Miller, NRC e
I J. E. Silberg, Esquire Resident Inspector, NRC p
S. S. Bajwa, NRC R. I. McLean, DNR A. W. Dromerick, NRC J. H. Walter, PSC 9810260056 981021 PDR ADOCK 05000317 S
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1--
0 ATTACHMENT (1)
UNIT 1 WIDE RANGE NOBLE GAS MONITOR SPECIAL REPORT Baltimore Gas'and Electric Company submits this Special Report concerning the inoperable Unit 1 Wide Range Noble Gas Effluent Radiation Monitor (WRNGM) Channel as required by Calvert Cliffi Updated Final Safety Analysis Iteport Section 15.3.1, Contingency Measure B.2.2.
ACTION TAKEN The Unit 1 WRNGM was removed from Operable status on September 23,1998, at approximately 1400, to support troubleshooting of the process flow transducer. The transducer was giving errant process flow signals that resulted in the WRNGM defaulting to " spec form" vice isokinetic flow control. It was determined that the transducer had failed hard and required replacement. Due to the unavailability of replacement parts, Calvert Cliffs defeated the input from the transducer to the WRNGM microprocessor, which forces the WRNGM to use " spec form" control under all operating conditions. A formal Operability Evaluation was written in accordance with plant procedures justifying operability under these conditiom.
EFFECT ON OPERATION In accordance with the Contingency Measure B.1 of Calvert Cliffs Updated Final Safety Analysis Report Section 15.3.1 and our Accidental Radioactivity Release Monitoring and Sampling Methods procedure (ERPIP-821), the preplanned alternate monitoring method was implemented. During the period that the Unit 1 WRNGM was not Operable, the Unit 1 Main Vent Radiation Monitor remained Operable. The inoperability of the WRNGM did not affect Unit 1 operation.
CAUSES OF INOPERABILITY The initial cause of the inoperability was the failure of the process flow transducer. The inoperability period was extended beyond the seven-day restoration time requirement due to the need to implement i
design changes to remove the input from the process flow transducer to the WRNGM microprocessor and to prepare the necessary operability evaluation.
PLANS AND SCHEDULES FOR RESTORING THE SYSTEM TO OPERABLE STATUS i
The Unit 1 WRNGM was returned to Operable status on October 9,1998, following the completion of the maintenance to remove the process flow transducer input to the WRNGM microprocessor and the completion of the formal operability evaluation. The WRNGM will operate in " spec form" control until the completion of additional design changes, which will, in part, replace the process flow transducer.
The estimated completion date of these design changes is August 31,1999.
The WRNGM was inoperable for approximately 16 days.
I